1. Technical Field
The present invention is directed to a window operator, and in particular, to a window operator having a worm and a worm drive system that can be selectively locked to the worm.
2. Background Art
Window operators having a worm with an integrally formed worm shaft to which a handle is permanently or releasably secured are known in the art. Such integrally formed worm shafts and associated handles can be seen in U.S. Pat. Nos. 5,272,837; 4,189,248; and 4,209,266, for example. With the worm secured to the window operator, the worm shaft and associated handle conventionally extend some distance from the window operator.
It is also known in the art to secure the above-described window operators to a window to form a window assembly which is shipped to the customer who then installs the window assembly in his or her home. Because of the additional clearance required to accommodate the worm shaft (and sometimes the handle) extending from the window operator, these window assemblies are expensive to package and to ship. Additionally, the handle and worm shaft can end up damaging other windows during installation if the windows are not kept spaced from each other a proper distance, in addition to damage to the operators themselves.
It is known in the art to conceal the worm shaft by disposing it in a passage in a wall and to remotely drive the worm by a handle via a temporary coupling. French Patent No. 2,467,954 discloses a window operator having a worm with an integrally formed worm shaft which is disposed at one end of a narrow passage which extends through a wall. A coupling is provided which extends from the worm shaft to the other end of the passage, where a handle may be used to rotate the worm via this coupling.
This window operator system does not address the problems disclosed above caused by the worm shaft extending from the window assembly prior to installation, such as the expensive shipping and packaging costs involved with such assemblies, or the damage to other windows caused during installation using such windows assemblies. In addition, the window operator system disclosed requires elaborate preparatory work to be performed on the wall prior to the installation of the window operator. The window operator system also discloses that the window operator be secured to the external surface of the building, where it is exposed to environmental factors, such as precipitation and extreme temperatures.
U.S. Pat. No. 5,493,813 also discloses a temporary coupling for a handle used in conjunction with a motor-driven window operator which has an alternative manual drive to be used to open and close the window. In one embodiment of the manual drive, a worm is coupled to a handle in an operative position. However, the handle is intended to be only temporarily coupled, even in the operative position, so as to not disturb the aesthetic appearance of the window. Consequently, the forces generated in opening and closing the window using the alternative manual drive can cause the male shaft to become separated from the female worm.
Further, neither French Patent No. 2,467,954 nor U.S. Pat. No. 5,493,813 address the problems associated with conventional operators, including the stresses encountered with an angularly oriented worm (which orientation is required for proper operation so that the person does not hurt himself or the window when turning the handle by banging his hand against the window) and the necessity that the handle as connected to the operator be essentially wobble free to provide a reliable and quality feel when being turned.
The present invention is directed toward overcoming one or more of the problems discussed above.